Method for cutting agatized petrified wood



Nov. 1, 1938.

J. R. CARPENTER METHOD FOR CUTTING AGATIZED PETRIFIED WOOD Filed Dec; 19, 1956 2 Sheets-Sheet 1 2 Sheets-Sheet 2 Nov. 1, 1938. J. R. CARPENTER METHOD FOR CUTTING AGATIZED PETRIFIED woop Filed Dec. 19, 195s Patented Nov. 1, 1938 f UNITED STATES PATENT OFFICE,

' LIETHOD FOR CUTTING AGATIZED PETRIFIED WVOQD r J. Ross Carpenter, Cheyenne, Wy0. Application December-19, 1936, Serial No. 116,734 2 Claims. (01. 1251-16) My invention relates to the art of cutting agatized petrified wood This material is veryhard, being'ratedasalmost as hard as the-diamond. The methods and apparatushertoiore used for this purpose have not been speedy-and accurate enough to make this ,valuable-and'highly ornamental ,material available for general use ina commercially practical manner.

The objects of my invention areto provide a .method and apparatus for cutting agatized petrifled wood at' relatively high speed to thereby greatly reduce the cost of forming it into articles of commerce, whereby this'material may be made commercially. available for manyornamental and usefularticles.

A further object is to provide means of simple andinexpensive construction ior holding articles of such irregular outline .as agatized petrified logs and pieces thereof, firmly in position so that 20. they may. be presented to the cutter with great 7 accuracyand cutjto any predetermined thickness,

and the cutting completed without any movement of other material ,being cut, and further in this.con-' nectionto provide means whereby the cutter may.

25. .be-firmlyand accuratelyheld in position relative to the material sothat the cutter will enter into and cut. from alog oi agatized petrified wood a relatively thin. slab. 7

'A" further object is to provide an apparatus 30 oi simple and inexpensive-construction foruse inpracticinglmy improved method of cutting.

:In the accompanying drawings, Figure 1 shows a front elevationof a mechanism embodying my invention, the caseportion being in section.

35 Figure .2 shows a longitudinal sectional view on the line 2-2 of Figure '1. a

Figure 3 shows I achorizontal sectional view on the. line 33-oi Figure 71. i

'Figure ishows a, detail view inrvertical trans- 40-verse sectionvofl a block 'of 'material 1being cut,

and the position of the; cutting blade when moving in one direction,.shown jby.solid lines, and when moving in the. opposite direction, by dotted lines. v 5 Figure 5 showsaverticaltransversesectional view ofrthe cementblock containing theragatized.

petrified woodand the base for supporting it upon the carriage.

Figure 6 shows alongitudinal sectional view of" 50, same,illustrating keris cut through the material;

and v Figure '7 shows aninverted perspective viewofthe cement block.

Myimproved apparatus comprises-a main 55,} frame lll-havinga track 1| thereon; Mounted on this-track is a movable carriage l2 for carrying the material to be cut. g V

For the purpose of adjustablyfixing thecarriage I 2 in proper 'position for cutting slabs of the exact thickness desired I'have providedupon 5 the top of the frame between-therailsof the track, a channel 13in which is deta'chably mounted at one-end a spacing bar I4 and'atthe other end a spacing bar I5, which latter bar is adjustablyconnected to the mainframe by the screw 10 Ilia. Adjacent this spacing bar [4 is a series of spacing blocks l6, each accurately proportioned to the exact width of the various'slabs-to be made of the material being out. To readjust the material being'cut, one of said spacing blocks I6 is 15 removed from the front of the material and re-- placed in the rear of the material being cut, thus providing ease and accuracy in the adjustment of the carriage to proper position.

Mountedin the main frame is' an upright clamping'framel1 containing a clamping screw l8 and a-follower l9 connected with the'screw for securely holding the material to be out upon the 'carriage and holding the carriage iirmly against thetrack.

on opposite sides of the carriageare the up-- right cutter guides 20, having slots 2| through which the cutter-frame is extended and guided in its reciprocating movement. I

The cutter frame 22 "ismounted in said slots and is provided with a cutter blade 23which may be made of cold rolled steel or the like, and which is smooth and of uniform thicknessthroughout its length. At one end of the cutter frame is a rigid arm'24 which is pivoted to a crank 25. This crank may; be operated in any'desiredmanner. When the crank is operated it imparts to the cutter blade a certain movement essential to the successful operation of my improved art of cutting agatized petrified'wood. This movement of 40 the cutter blade is as follows: When the crank is 'at.its lower limit of movement, the portion of the blade nearest the crank'engages the material being cut, and theother portion of the blade is elevatedout. of contact with said material, then when the. crank is at its upper limit of movement the portion of the cutter blade furthest from the crank engages the material being cut, and the portion nearest the crankis elevated out of contact therewith. This peculiar movement of the blade enables me to practice my improved art of cutting in arapid manner.

"The material to becut comprises logs and broken-pieces of'agatized petrified wood of very irregular outline and very difficult to firmly and moving out of the kerf, is tilted to position out of contact with the'kerfat the opposite side thereof, and into contact'with the kerf at-the securely hold in position to be cut. I have provided means of simple and. inexpensive character for firmly'holding such material in position and for cutting it with great accuracy into the sizes desired.

I provide a mould box 30, shown in Figure 5, into which the material to be cut is placed, then the mould 1's filled with cement and permitted to set and harden. This mould is provided with grooves 3| in its bottom portion so that the block of cement 32, when removed, is provided with. ribs 32a. I then provide a base block 33 formed with grooves shaped to receive and accurately fit the ribs 321%. Then the base block is placedupon' the carriage and firmly fixed there0n. When placing the material to be out within the mould,

I carefully measure the position of each'piece of j material relative to the end of the mould, and make a record thereof. Then when the cutting is being done, I can cut each piece of the material at the desired place to formthe-kind of articles desired; 'InFigure 6 the kerf 34 is shown in-position for "cutting-a thin slabfrom the log 35. In

view of the'extreme hardness of the agatized petrified woodthis operation is very difficult. I have demonstrated, however, in actual practice that when the'material to be cut is embedded in a cement block the cutter will enter a log of agatized petrified wood'at the angle shown in said figure, therebyenablin'g me to cause the cutterto enter a log of agatized petrified wood at any desired angle relative to the surface thereof. When cut ting broken pieces of the material marked 36, theymay be'placed in the mould while the ocment is being poured, and positioned one above the other, then the cutter may be accurately positioned to cutthrough all 'of said brokenpieces' in one operation, thereby all of them accurately in one dimension, say, for instance, six inches thick. They are finally reduced-to the desired dimension otherthan thickness by succeeding cutting operationsin another cement block. r

The blade'is reciprocated by the crank and is tilted during this reciprocation. -Its .action' is so arranged that during the movement of the blade in one direction, the blade will engage the article at one "end of the kerf being formed, and during this movement the other end of the blade which is middle portion thereof, as shown by dotted lines in Figure 4. A similar action takes place in the opposite direction during the return movement ofthe blade, as shown by solid'lines in Figure 4. This movement of the blade accomplishesthe following desirable results:

,At the ends of the kerf the blade engages only when moving inwardly towardathe middle of thematerial, thus preventing chipping ofi. ofpar-.

ticles of the material at those points such as would occur if the blade engaged the ends of the kerf while cutting outwardly. Furthermore, this movement of the blade keeps 'theliquid carrying the abrasive, hereinafter described, Within the kerf.

fora relatively long time as it continuously moves it from the ends of the kerf toward the center of the material being out.

The 7 liquid containing the bentonite and the abrasive will fiow by gravity from the middle portion of the material being cut because thebottom of the jkerf inclines downwardly in-both directions from" the middle, andthe cutter blade continuously tends to move the-said liquid toward the middle of the material being out. By reason of these two opposing actions the said liquid is contained Within the kerf for a relatively long time,

and such liquid as flows from the ends of the kerf is returned as hereinafter described.

Beneath the cutter blade I have formed in the frame a sump 26 in which there is mounted a pump 21. A pipe 28 leads from the pump to a point above the kerf to returnthe liquid to the blade after it has passed into the sump.

In practicing my improved art I first provide a quantity of bentonite and mix it with sufficient water to form a slippery plastic gelatinous mass that resembles soft soap (see Bentonite, its properties, mixing, preparation and utilization, by

C..W. Davis and ,H. C. Vacher, Technical Paper 438, Dept. of Commerce, United States of America) I thenthoroughly mix with' the wetted mbentonite a quantity of finely divided carborundum or other abrasive. I have had satisfactory results with 60 mesh carborundum. After said mixing, the carborundum is held in suspension in r the bentonite, and I find that due to thisfsuspen- V sion I'have been able to obtain such satisfactory I results. I then, by the operation of the pump,

force the liquid into the kerf, thus applying said mixture to the surface of the cutter blade andv that portion of the material being out, and .then operate the cutting blade. Y

,When carborundum alone in finely divided condition is placed between the cutting edge of a reciprocating blade and agatized petrified wood,'.

the carborundum rapidly-becomes dull and shattered, and cutting proceedsvery slowly. However,

when my process is employed I find that the cutting proceeds rapidly and. that the carborundum and bentonite may be used repeatedly.

I believe that the reason for this apparent.

phenomenon :is as follows: The cutting blade made of-cold rolled steel or other similar metal is relatively porous as compared with the agatized petrified wood, and individual abrasive particles orsmall groups of them' brought beneath the blade by the raising and lowering thereof during its reciprocating motion, slide along with the blade and cut away portions of the material. If,

however, these particles of carborundum were per-r manently lodged in the pores of the cutter blade,

they would soonbecome dulled. ordestroyedf With my improved apparatus, however, the abrasive-charged cutting edge of the bladeis continuously being pressed against and removed from the material. When the blade is thus removed, the

gelatinous nature of the bentonite causes quan-.

blade it is graduallyreduced in quantity by being drawn out through the ends of the cut by force of gravity. This material may be pumped up and repeatedly re-applied to the cutter blade'for a considerable number of times before the carbon rundum becomes appreciably or extremly fine and the speed of cutting is decreased.

Another advantageof my improved method is that when a cut is completed through the agatized petrified wood, the faces of the material smooth, finished appearance.

are free from scratches or grooves and present a This desirable result is attained because, during a cutting operation, the liquid containing the abrasive is at all times present between the sides of the cutter blade and the adjacent sides of the material being cut, and since there is very little lateral pressure of the blade against the sides of the kerf, the action at the sides of the blade is a smoothing, polishing action, as distinguished from the cutting action before described, at the cutting edge of the blade.

To illustrate this action, it is my present practice in actual use with a full sized machine to use a cutting blade until the under surface is worn away to a great extent. I then reverse the blade so that the former cutting edge is uppermost, and then use the blade in that manner until the new cutting edge is worn away to such an extent as to require a new blade. When this occurs at such time as the material is out say half way through, I insert a new blade of the same size and thickness as the original blade, and find that it functions properly and completes the out without any appreciable binding in the cut or unevenness in the surfaces of the kerf.

I claim as my invention: 7

1. The method of cutting kerfs in agatized petrified wood, which consists in providing a thin, smooth blade made of a metal having a degree of porosity greater than that of agatized petrified wood, providing a jelly-like substance containing in suspension therein a quantity of-abrasive particles of such size that they will enter and become lodged in the pores of the blade and will not enter and become lodged in agatized petrified wood, placing a quantity of said jelly-like substance containing said abrasive particles in contact with both the blade and the material to be out, then reciprocating the blade against the material being cut, thereby causing portions of said abrasive particles to enter and become lodged in the pores of the blade and be carried by the blade in cutting contact with the material being cut and not lodged in the material being cut, to

thereby avoid having said abrasive wear away the blade, then at times during the reciprocation of the blade, causing portions of its cutting edge to move away from contact with the material being cut, to thereby cause some of the abrasive particles carried by the blade to adhere to the material being out, due to the adhesive quality of the said jelly-like substance, and thereby be withdrawn from the pores of the blade and thereafter returning said portions of the blade to contact with the material being cut and the jelly-like substance thereon to thereby cause other particles of said abrasive substance to enter the pores of the blade and present previously unused particles of the abrasive to cutting positions projecting from the blade.

2. The method of cutting kerfs in agatized petrified wood, which consists in providing a thin, smooth blade made of a metal having a degree of porosity greater than that of agatized petrified wood, providing a jelly-like substance containing in suspension therein a quantity of abrasive particles harder than agatized petrified wood and of such size that they will enter and become lodged in the pores of the blade and will not enter and become lodged in agatized petrified wood,placing a quantity of said abrasive substance in contact with both the blade and the material to be cut, then reciprocating the blade against the material being out, thereby causing portions of said abrasive particles to enter and become lodged in the pores of the blade and be carried by the blade in cutting contact with the material being cut and not lodged in the material being cut, to thereby avoid having said abrasive wear away the blade, then at times during the reciprocation of the blade, causing portions. of its cutting edge to move away from contact with the material being cut, to thereby cause some of the abrasive particles carried by the blade to adhere to the material being cut, due to the adhesive quality of the said jelly-like substance, and thereby be withdrawn from the pores of the blade and thereafter returning said portions of the blade to contact with the material being cut and the jelly-like substance thereon to thereby cause other particles of said abrasive substance to enter the pores of the blade and present previe ously unused particles of the abrasive to cutting positions within the pores of the blade and causing said blade during its reciprocation to first move upwardly and toward the center of the material from one side andthen upwardly and toward the center of the material from the other side, to thereby carry the jelly-like substance toward the center of the material being cut.

J. ROSS CARPENTER. 

